1. Field of the Invention
The present invention relates to a magnetic recording apparatus provided with a magnetic core adapted to read and write magnetic information while moving relative to a magnetic recording medium which is rotated and, in particular, to a technique which makes it possible to prevent the trailing side corner portion of a slider main body from being brought into contact with the magnetic recording medium when the slider main body flies in an inclined state with respect to the magnetic recording medium.
2. Description of the Related Art
Conventionally, a magnetic recording apparatus having a construction as shown in FIG. 7 has been known as an information recording apparatus for a personal computer or the like.
In the magnetic recording apparatus M shown in FIG. 7, a plurality of disc-like magnetic disk 100, on which magnetic layers are formed, are rotatably provided on a chassis 101, and a plurality of magnetic heads 102 are provided so as to be capable of moving relative to the obverse or the reverse side of each of these magnetic disk 100. Each of these magnetic heads 102 is individually supported by a base 105 through the intermediation of a thin and narrow load beam 103 in the form of a triangular plate and an arm 104, and this base 105 is rotatably supported on the chassis 101. That is, in the construction shown in FIG. 7, the base 105 rotates to thereby cause the magnetic heads 102 to move radially relative to the magnetic disks 100, and magnetic information at desired positions on the magnetic disk 100 is read, or magnetic information is written to desired positions on the magnetic disks 100.
The base 105 rotates around a rotation shaft 106 arranged parallel to the rotation shaft 100 of the magnetic disks 100 to thereby cause the magnetic heads 102 to move radially over (or under) the magnetic disks 100, whereby the support structure for the base 105 shown in FIG. 7 is realized. The structure for driving the base 105 shown in FIG. 7 is a voice coil motor structure in which a voice coil 108 and an electromagnet 109 are combined. Apart from this, a variety of structures are known as base driving mechanisms, such as a drive structure using a linear motor.
FIG. 8 shows the above magnetic head 102 in a condition in which the medium facing side thereof is directed upwardly. This magnetic head 102 mainly comprises a plate-like slider main body 111 consisting of a non-magnetic material such as ceramic, and a magnetic core 112 having a coil portion provided at the center of the end surface at one end of the slider main body 111. In the slider main body 111 of the magnetic head main body 102, the inner side of FIG. 8 is the leading side 113 on the upstream side with respect to the rotating direction, and the near side is the trailing side 115 on the downstream side with respect to the rotating direction. Further, at the end of the leading side 113 of the slider main body 111, there is formed a protrusion 117 having an inclined surface 116. Further, main rail portions 118 are formed on both sides of the slider main body 111, and a sub rail portion 119 is formed at the center of the end portion on the trailing side 115 of the slider main body 111.
In the magnetic head 102 shown in FIG. 7, the rail portions 118 and 119 receive positive pressure by the air flow generated as a result of the rotation of the magnetic recording medium 100, so that it flies over the obverse or reverse surface of the magnetic recording medium, and in this condition, it reads the magnetic information of the magnetic recording medium 100 or writes magnetic information to the magnetic recording medium 100.
A flying system called a lamp load system has recently been adopted for use in the magnetic head of conventional magnetic recording apparatus. In this system, a retraction portion having an inclined surface is provided on the side of the rotated magnetic recording medium so as to be spaced apart therefrom, and when the rotation of the magnetic recording medium is stopped, the magnetic head 102 which has been flying over the magnetic recording medium is moved to the retraction portion side by way of the inclined surface of the retraction portion, whereby there is no fear of the magnetic head 102 adhering to the obverse or reverse side of the magnetic recording medium 100 when the rotation of the magnetic recording medium 100 is stopped.
In contrast, in the conventionally used magnetic head of CSS (contact start stop) system, the magnetic head is pressed against the obverse or reverse surface of the magnetic recording medium due to the elastic force of the load beam or the flexure when the rotation of the magnetic recording medium is stopped, so that if both the surface of the magnetic recording medium and the slider portion of the magnetic head are mirror-finished, the magnetic head 102 is liable to adhere to the surface of the magnetic recording medium, and, due to the adhesion, there is a fear of the magnetic head undergoing crashing.
In the magnetic head of the lamp load system described above, the magnetic head is retracted to the side of the magnetic recording medium when the rotation of the magnetic recording medium is stopped, so that there is no fear of the magnetic head undergoing adhesion, and it is possible to provide a magnetic head in which there is little fear of crashing being generated. In the lamp load system, however, there are problems as described below.
In the magnetic head of the lamp load system, the slider main body, which moves in the radial direction of the magnetic recording medium along the inclined surface of the retraction portion to move to the obverse side or the reverse side of the magnetic recording medium, may approach the obverse or reverse side of the magnetic recording medium while maintaining the condition in which it is inclined by a minute angle (approximately 1xc3x9710xe2x88x925 rad) (the rolling state in which one side with respect to the width direction of the slider main body is above or below). It is to be assumed that the inclination angle of at this time is very minute. However, due to the fact that the magnetic head approaches the magnetic recording medium in an inclined state, there is a possibility of the acute corner portion of the slider main body of the magnetic head being brought into contact with the magnetic recording medium.
For example, in the case of the slider main body 111 of the magnetic head 102 shown in FIG. 8, the leading side 113 is greatly spaced apart from the magnetic recording medium 100 due to the air pressure as a result of the rotation of the magnetic recording medium 100, and the trailing side 115 is somewhat closer to the magnetic recording medium 100, 50 that when it flies, the end portion on the trailing side 115 of the magnetic head 102 is closest to the magnetic recording medium 102. However, in a case in which, as described above, the magnetic head 102 transversely approaches the magnetic recording medium 100 in the radial direction along the inclined surface of the retraction portion from the condition in which it is inclined, and then starts to fly, the slider main body 11 is brought into an inclined state in which rolling occurs, and in the initial state in which the flying attitude is assumed, one of the end portions 120 on both sides with respect to the width direction of the trailing side 115 of the slider main body 111 of FIG. 8, approaches closest to the surface of the magnetic recording medium 100, with the result that there is a fear of one end portion 120 being brought into contact with the surface of the magnetic recording medium 100.
In particular, it is to be assumed that this problem is liable to be generated when an impact or load is applied from outside at the time of lamp loading, in which the flying attitude is assumed after bringing the magnetic head 102 close to the magnetic recording medium 100 and, further, at the time of seeking, in which the magnetic recording head 102 is moved to the outside of the magnetic recording medium 100.
Conventionally, to prevent this problem, the end portion on the trailing side 115 of the magnetic head 102 is ground with a grinding tape to round it off. However, it is difficult to achieve a high accuracy in machining, and further, the cost of machining can be prohibitive.
The present invention has been made in view of the above problem. Accordingly, it is an object of the present invention to provide a structure in which, when the slider main body of the magnetic head flies over the magnetic recording medium, there is no fear of the end portion on the trailing side of the slider main body coming into contact with the magnetic recording medium to damage the same.
A second object of the present invention is to provide a structure in which, when a magnetic head of the lamp load system is adopted, if there is a fear of the edge portion on the trailing side of the slider main body of the magnetic head being brought into contact with the magnetic recording medium due to the flying attitude, the protrusion formed is not acute but rounded off to thereby prevent the magnetic recording medium from being damaged.
To achieve the above objects, there is provided, in accordance with the present invention, a magnetic head comprising a magnetic head slider including a slider main body which flies with a medium opposing surface being directed to a rotated magnetic recording medium and which is provided with a magnetic core for performing recording or reproduction of magnetic information, wherein there is provided on the medium opposing surface of the slider main body a rail portion for flying, wherein, in the slider main body, the upstream side with respect to the rotating direction of the magnetic recording medium is the leading side, the downstream side with respect to the rotating direction being the trailing side, and wherein there is provided in a corner portion of the medium opposing surface on the trailing side of the slider main body a protrusion which is lower than the rail portion and which is closer to the magnetic recording medium than the end portion on the trailing side of the slider main body in the rolling state of the slider main body.
When the slider main body is to run while being inclined with respect to the magnetic recording medium so as to cause rolling, one of the end portions with respect to the width direction on the trailing side of the slider main body approaches the magnetic recording medium. If, in this case, an impact or load applied from outside, the protrusion comes into contact with the magnetic recording medium before the end portion on the trailing side of the slider main body comes into contact with the magnetic recording medium. By making the configuration of this protrusion such that it is not acute as the corner portion of the end portion of the slider main body, there is no fear of the magnetic recording medium being damaged if the protrusion comes into contact with the magnetic recording medium.
In accordance with the present invention, there is further provided a magnetic head comprising a magnetic head slider including a slider main body which flies with a medium opposing surface being directed to the rotated magnetic recording medium and which is provided with a magnetic core for performing recording or reproduction of magnetic information, wherein, in the slider main body, the upstream side with respect to the rotating direction of the magnetic recording medium is the leading side, the downstream side with respect to the rotating direction being the trailing side, wherein a rail portion for flying the slider main body is formed on the medium opposing surface of the slider main body so as to extend from the leading side to the trailing side, and wherein there is provided in the end portion on the trailing side of the rail portion a rail step portion which is positioned in a corner portion of the medium opposing surface on the trailing side of the slier main body and which is lower than the other portion of the rail portion.
The rail step portion formed on the trailing side of the rail portion causes the trailing side of the magnetic head to fly by generating positive pressure when the magnetic head flies, so that the force with which the trailing side of the magnetic head is brought into contact with the magnetic recording medium is restrained. Thus, if rolling is caused in the magnetic head by an impact or load from outside, it is possible to prevent the end portion on the trailing side from hitting hard against the magnetic recording medium. Further, it is more desirable to round off the corner portion on the trailing side of the rail step portion.
In the magnetic head of the present invention, the rail portion is provided with a sub rail portion formed at the center of the medium opposing surface on the trailing side of the slider main body, and a main rail portion formed so as to extend from the leading side of the slider main body positioned on the upstream side with respect to the rotating direction of the magnetic recording medium to the trailing side of the slider main body, and a magnetic core is formed in the vicinity of the sub rail portion, and the height of the protrusion or the rail step portion is smaller than the height of the sub rail portion.
In the magnetic head of the present invention, the relationship: (L1xc3x97h1/L2) less than h2 less than h1xe2x88x92(L2xe2x88x92L1)xc3x9710xe2x88x925 (mm) holds true, where h1 is the height of the sub rail portion, h2 is the height of the protrusion, L1 is the distance from the side surface of the slider main body to the protrusion, and L2 is the distance from the side surface of the slider main body to the sub rail portion.
By adjusting the height of the protrusion so as to satisfy the above relationship, the protrusion does not become lower than the sub rail portion if rolling is caused in the magnetic head and the magnetic head is inclined by approximately 1xc3x9710xe2x88x925 rad, so that it is possible to prevent the end portion of the slider main body on the trailing side of the magnetic head from colliding with the magnetic recording medium.
In the magnetic head of the present invention, protrusions are formed on both sides of the sub rail portion, each protrusion being formed in a round or elliptical configuration rounded off by not less than 5xc3x9710xe2x88x926 m.
When the protrusion is formed in a round or elliptical configuration, there is little fear of the magnetic recording medium being damaged if the protrusion comes into contact with the magnetic recording medium.
In the magnetic head of the present invention, the slider main body is composed of a min body portion which occupies the greater portion of the leading side and the trailing side and which is formed of a non-magnetic hard ceramic material, and an insulating layer formed by coating at the end portion on the trailing side of this main body portion, wherein the magnetic core is embedded in the insulating layer, the protrusion being formed in the border portion between the main body portion and the insulating layer.
In accordance with the present invention, there is further provided a magnetic recording apparatus comprising a magnetic head as described above, a magnetic recording medium which is rotated, and a supporting mechanism for moving the magnetic head in the radial direction of the magnetic recording medium.
In a magnetic recording apparatus provided with the above-described magnetic head, if an impact or load is applied from outside, there is little fear of the magnetic recording medium being damaged by the magnetic head which is running.